Systems and methods to prevent contamination of potable water with lead and/ or iron, and to extend the useful life of the potable water system, while reducing maintenance and capital costs

ABSTRACT

Provided are systems and methods for preventing corrosion, and lead and iron contamination in potable water piping systems comprising lead, non-electrically conducting, and/or iron pipes. A sacrificial/potential anode, made of a material, such as a metal or metal alloys less noble than iron, e.g., zinc, aluminum, magnesium, and/or alloys thereof, is electrically attached to the potable water piping system. Alternatively, an active cathodic corrosion prevention system may be used. The active cathodic corrosion protection system comprises an independent source of DC power, a voltage controller and a non-sacrificial or a sacrificial/potential grounding anode. The negative terminal of the voltage controller is connected to the potable water piping system. The interior surface of the lead and/or iron pipe is maintained at a voltage and/or potential above the reduction potential of the redox reactions between the disinfection chemicals and the interior surfaces of the lead and iron pipes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims to priority to U.S. Provisional UtilityApplication Ser. No. 62/388,798 filed Feb. 8, 2016, the contents ofwhich are incorporated herein by this reference. This Application isalso a Continuation-in-Part of application Ser. No. 15/177,770, filedJun. 9, 2016, and a Continuation-in-Part of application Ser. No.14/811,629, filed Jul. 28, 2015 the contents of both applications areincorporated herein by this reference.

TECHNICAL FIELD

This invention relates to potable water delivery systems, and morespecifically, systems and methods for preventing lead and ironcontamination of potable water by the lead and iron delivery system. Themethod controls the internal corrosion by controlling the chemical redoxreaction between the protective concentration of disinfection chemicalsand the iron and lead metal pipes. The internal corrosion is preventedby maintaining the redox reaction in cathodic mode by impressing acathodic potential on the system equivalent to, or higher than thecathodic potential of the redox reaction. External corrosion isprevented by the cathodic corrosion protection method, employing asacrificial anode. Depending on conditions, this sacrificial anode mayprovide a high enough potential to control the internal redox reactionin cathodic mode. In such case, the anode is referred to as asacrificial/potential anode.

BACKGROUND

During the late 19th century and early part of the 20th century,building codes required that cast iron pipe be used for mains, and leadpipe be used from the mains to the point of delivery of potable water.Many of these systems remain in use today, but over time, some pipecomponents have failed. By mid-century, failed components had beenreplaced with plastic components, which resulted in unintended andundesirable consequences, including contamination of the potable waterwith iron and lead.

The potable water is delivered to the distribution system (whichincludes the mains and the other piping components from the mains to thepoint of delivery) essentially lead and iron free. A small excess ofdisinfectants (chlorine, bleach, ozone, and/or other oxidants) referredto as a protective concentration, is left in the purified water toassure its purity at point of use, should the water become contaminatedduring delivery. This 1-4 ppm of chlorine or other oxidants can reactwith the interior of the iron mains and the lead piping, causingcorrosion.by a redox reaction between the excess disinfectants and thelead and iron. However, the amount of iron corroded from the iron pipesis not enough to exceed permissible concentrations of iron in potablewater, nor is it great enough to reduce its service life by anunacceptable amount.

Regarding lead, so long as the lead and iron pipes remain in electricalcontact the lead does not corrode because it is at the reductionpotential of iron, which is considerably higher than the reductionpotential of lead. Additionally, should lead be present in the water,some would be plated on the iron.

However, the ageing iron and lead potable water distribution systems canno longer reliably deliver potable water that meets the currentregulatory standard for lead content. Corroded iron mains are beingrepaired with plastic, thus breaking the electrical conductivity of thedistribution system, which in turn negates the cathodic potentialprotection of the lead pipes. Consequently, the protective concentrationof purification chemicals left in the potable water is corroding theinterior of the lead pipes in a redox reaction, thus adding unacceptableamounts of lead to the water. This redox chemical reaction is generallynot recognized by the potable water suppliers, or consumers as a sourceof lead contamination. Consequently, the lead contamination is ascribedto different sources. As a result, inappropriate, ineffective, andcostly actions are taken in an attempt to correct the leadcontamination.

Lead poisoning is a serious health concern, and even small amounts oflead can cause serious health problems. Infants and children under theage of 6 are especially vulnerable to lead poisoning, which can severelyaffect mental and physical development. At very high levels, leadpoisoning can be fatal. As a result of the corrosion of the lead pipes,children may be physically and/or mentally damaged before the leadcontamination is discovered and corrective action taken. Theintelligence deficit and the tendency toward violent behavior is carriedinto adult life resulting in undesirable consequences, such as povertyand crime.

Corrosion inhibiting reagents are being used to mitigate this problem ofiron and lead corrosion to a limited success. In some cases, to solvethe problem, the lead pipe is being removed and replaced with copper orplastic piping. This is costly, and although this may solve the leadproblem, it introduces a similar problem of copper corrosion and leavesthe failing iron mains to be dealt with at a future date.

Other corrective actions can be very costly and may range from a fewmillion dollars to supply bottled water for an extended period of time,or to complete replacement of the potable water distribution system at acost of perhaps several billion dollars and the bankruptcy of acommunity.

There is, therefore, a need for potable water systems and methods thatpreemptively prevent or reduce the corrosion of iron and lead pipes inpotable water systems.

SUMMARY

It is an object of this invention to limit the lifelong loss ofintellectual capacity and tendency to violent behavior due to leadpoisoning, particularly of infants, young children, and to a lesserextent, of adults.

It is a further object of this invention to reduce the level of violenceand criminal activity in older sections of our cities that requiresadditional policing to maintain order by reducing lead poisoning bypotable water of children and adults.

It is also a further object of this invention to provide a relativelyinexpensive way to control the lead content of potable water toregulatory standards, and to extend the useful life of the existingpotable water distribution systems.

In accordance with the foregoing objectives and others, exemplarysystems and methods are disclosed herein that can be used to prevent orreduce the corrosion of iron and lead pipes in potable water systems.

Each electrically isolated section of lead pipe is electricallyconnected to a grounded zinc or zinc alloy mass or other more cathodicmetal or metal alloy, which serves as an electrode. This type of metalmass is commonly referred to as a sacrificial anode, and the process, ascathodic corrosion prevention. This method is commonly used to preventthe exterior corrosion of metals in contact with an electrolyte that isshared with the sacrificial anode. However, in this case, there are twopurposes for the anode; firstly, to protect the iron pipe from exteriorcorrosion resulting from contact with soil or water electrolyte;secondly, to prevent the interior of the iron and lead pipes fromcorrosion by their redox reactions with the protective concentration ofdisinfectant chemicals, left in the potable water. This later objectiveis achieved by raising the internal potential of the pipes to, orbeyond, the cathodic potential of their respective redox reactionpotentials. It is recognized that so long as the lead is electricallyconnected to the iron, the lead is protected by the reduction potentialof the iron. Alternatively, or in addition to, each electricallyisolated section of iron or lead pipe is electrically connected to agrounded mass of zinc metal, zinc metal alloy, or a lesser noble metalsuch as aluminum or magnesium, or alloys thereof, or other source ofappropriate electrical potential.

Alternately, the potential of the iron and lead pipes can be raisedabove their reduction potentials by connecting them to a source of DCpower of appropriate potential above ground.

Because the sacrificial anode and the iron and lead pipes share aconnection through the ground which acts as an electrolyte, thesacrificial anode and the external surfaces of the iron and lead pipescreate an electrolytic cell which generates an electrical current thatcorrodes the anode and prevents corrosion of the exposed surfaces of theiron and lead cathodes. Because metallic iron has a higher reductionpotential than lead, and because the iron and lead are electricallyconnected, and because the impressed DC voltage required to assure thatthe redox reaction between the iron and the protectant concentration ofdisinfectant chemicals is cathodic and at least equivalent to thereduction potential of iron, both the exterior and interior, the entiredistribution system is protected from corrosion. By this method, allelectrically connected metallic system components with reductionpotentials more noble than the impressed cathodic voltage are protectedfrom corrosion.

The details of one or more embodiments of the subject matter of thisspecification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and not limited to thefigures of the accompanying drawings, in which like references indicatesimilar elements and in which:

FIG. 1 illustrates a passive corrosion prevention system according toone embodiment of the invention.

FIG. 2 illustrates an active corrosion prevention system according toone embodiment of the invention Note that an electrical conductor isused to bridge a non-conducting section such as a break and/or a plasticrepair.

FIG. 3 illustrates the use of fire hydrants and /or other above groundmetal components as points of electrical connection to the distributionsystem.

DETAILED DESCRIPTION

The following detailed description includes references to theaccompanying drawings, which form a part of the detailed description.The drawings show illustrations in accordance with example embodiments.

The systems and methods disclosed herein for preventing corrosion oflead and/or iron piping comprise electrically attaching a dedicatedcathodic corrosion protection system to the lead and/or iron pipes. Thepassive cathodic protection system may comprise a sacrificial anode ormultiple anodes made of, zinc metal, zinc alloy, or a lesser noble metalsuch as aluminum or magnesium, or alloys thereof. Thesacrificial/potential anode is in contact with the ground andelectrically connected to the lead and/or iron pipes. Thesacrificial/potential anode maintains the lead and/or iron pipes at avoltage above the pipes' respective reduction potentials, thuspreventing the external corrosion of the lead and/or iron pipes. If thesacrificial/potential anode creates a cathodic potential high enough tomake the redox reaction between the protective concentration ofdisinfection chemicals cathodic, then the interior of the pipes will beprotected from corrosion.

Alternatively, an active cathode corrosion protection system supplied byan independent electrical energy source may be used. The positiveterminal of the active system is connected to ground by either aconducting non-sacrificial anode or a sacrificial anode. The negativeterminal is connected to the lead and/or iron pipes. The voltage betweenthe grounding anode and the lead and/or iron pipes is maintained at alevel at, or above, the pipes' respective reduction potential, and thecathodic potential of the redox reaction between the pipe interiorsurface and the disinfectant chemicals. It must be understood that thenecessary cathodic potential to make the redox reaction between the pipeinterior and the disinfectant chemicals is dependent on theconcentration of the chemicals and the temperature of the system.

FIG. 1 shows an example embodiment of a lead pipe corrosion preventionsystem according to the present invention. Iron main 110 providespotable water from a water source. Lateral 120 provides water from ironmain 110 to a lead pipe 170, possibly through service connection 130.The delivery system is comprised of iron main 110 and lateral 120, andis generally underground, as indicated by the cross hatches. If lateral120 is plastic, a conducting jumper 140 is used between the iron main110 and lead pipe 170 in order to maintain electrical continuitythroughout the delivery system. Note that, for clarity, only a portionof the ground is shown crosshatched.

The present invention adds sacrificial anode 180, which is electricallyconnected to the lead piping by, e.g., electrical conductor 190 andclamps 200. While electrical conductor 190 and clamps 200 are providedas an example, any means of electrically connectingsacrificial/potential anode 180 to the lead piping may be used, and oneof ordinary skill in the art will recognize other such connections. Atleast part of sacrificial/potential anode 180 is grounded, as indicatedby the cross hatches in FIG. 1. Furthermore, while FIG. 1 only shows onesacrificial anode 180, more than one sacrificial anode may be used.Sacrificial anode 180 is comprised of zinc, a zinc metal alloy, or amore cathodic metal or alloy. One of ordinary skill in the art willrecognize other materials that may be used. Sacrificial anode 180maintains the lead pipe at a voltage above the reduction potential ofiron and thus the reduction potential of lead and the reductionpotential of the redox reaction between the disinfectant chemicals andlead and iron. Consequently, both the exterior and the interior, of boththe iron and the lead pipes are protected from corrosion Thus, both theiron and the lead in the deliver water, added from the delivery systemare reduced to a level of little concern, perhaps ppts. Thus, the healthproblems caused by lead contamination of potable water by the deliverypipes are prevented.

The ground medium provides the electrical return leg of the electrolyticcircuit. The required size of sacrificial anode 180 depends on the sizeand length of the distribution system. The required number and locationof sacrificial anodes 180 is dependent on, whether, or not, the leadpipe is electrically connected to the iron main. The iron main acts as asacrificial/potential anode for the lead pipe. If the lead pipe is notelectrically connected to the iron main, a separatesacrificial/potential anode connected to the lead pipe is required toprotect the lead pipe from both external and internal corrosion.

FIG. 2 illustrates an alternate embodiment of the present invention, anactive cathodic corrosion protection system for both the iron and leadpipes. This system is substantially the same as the system described inFIG. 1, but with a DC voltage from an independent power sourcecontrolled at a voltage above the reduction potentials of the iron andthe cathodic redox potential of the iron and disinfectant chemicals, isimpressed on the lead or iron pipes. In this system, iron main 110 andlateral 120 are substantially the same as described with respect toFIG. 1. In this system, however, either an electrically conductinginsoluble anode or a sacrificial/potential anode 210 is used to contactground. Insoluble anode 210 may be made of an insoluble material, suchas graphite. One of ordinary skill in the art will recognize othersuitable materials for insoluble anode 210. Insoluble anode 210 iselectrically connected to a DC power source 220 and voltage controller230. DC power source 220 is electrically connected to the variablevoltage controller 230. The DC power source 220 may be any source ofdirect current power, of appropriate voltage, including but not limitedto a storage battery or an AC/DC rectifier converter. The variablevoltage controller's 230 negative terminal is electrically connected tothe lead or iron pipe, for example, the negative terminal of variablevoltage controller 230 may be electrically connected to the lead pipe.Variable voltage controller 230 will permit the cathodic voltage to beraised or lowered to control the concentration of lead and/or iron inthe potable water at point of delivery. The cathodic voltage may beincreased to protect greater areas of the distribution system, as wellas for changes in the protective concentration of disinfecting chemicals

Multiple sacrificial/potential anodes and/or DC voltage sources may beconnected to any part or parts of the electrically connected potablewater distribution system so as to, maintain a desired uniform voltagethroughout the entire potable water distribution system.

Fire hydrants, control valves, and flow meters are above groundcomponents that can be utilized as connection points; FIG. 3 to diagnosethe electrical continuity of the distribution system, to bridgeelectrical breaks with surface jumper cables, and to install thiscathodic corrosion protection system. By utilizing above ground surfacecomponents, the corrosion protection can be installed without excavatingto gain access to the underground pipes of the distribution system. Thisis of major significance when the water mains are located under streetsor, other infrastructures.

Similar systems may be used to limit or prevent corrosion of iron pipes.A passive corrosion prevention system for iron pipes includes thecomponents described in FIG. 1, but the sacrificial/potential anode iscomprised of zinc metal, zinc metal alloy, or a lesser noble metal suchas aluminum or magnesium, or alloys thereof.

An active corrosion prevention system for iron pipes includes thecomponents described in FIG. 2, but the voltage is controlled at avoltage above the reduction potential of iron.

The present invention prevents the excessive lead and/or ironcontamination of the potable water, while extending the service life ofthe iron mains and lead laterals by using cathodic corrosion protectiontechniques for protecting the exterior surfaces of the lead and ironpipes and potential to control the reaction protect at great savingsover the

Additional benefits of this invention include: 1) the cathodic potentialwill prevent pinhole corrosion of any copper tubing in the distributionsystem and in the final plumbing; 2) water loss will be reduced; 3) thecost to maintain the potable water distribution system will be reduced;and 4) the use and cost of water purification chemicals will be reducedby eliminating the need for corrosion inhibitors, and less disinfectionagent.

Additional Notes:

The protection methods are implemented by electrically connecting to afire hydrant or multiple hydrants, valves, or flow meters.

Bypass breaks and non-conducting repairs to the iron mains by installingelectrical conductors between hydrants located on opposite ends of thebreak, thus restoring electrical continuity of the underground systemwithout disturbing the ground surface.

Bypass electrical continuity breaks in lead laterals by installingmetallic jumpers between a fire hydrant and a water meter on thelateral.

Detect the local level of cathodic corrosion protection by measuring theelectrical potential between a hydrant and the ground

Connect the protective power source to a hydrant to boost a decayedprotective voltage to protection levels.

Reduce maintenance and capital costs and extend the useful life of thepotable water system by implementing these claims that also reduces theiron and lead contamination in the delivered potable water to regulatorylevels. (we are assuming that the water purification plant is deliveringwater with lead content that meets regulatory specifications.)

The corrosion protection system prevents the potable water from beingcontaminated with lead and iron by the existing water distributionsystem when this process is implemented. The system maintenance andcapital costs are reduced by using surface components such as firehydrants to electrically detect and correct existing undergroundelectrical faults. Further, fire hydrants are conveniently availablethroughout the system and can be used to monitor the system's protectivevoltage, and to provide a local connection to the distribution system toboost any decayed protective voltage. Once preexisting conditions arecorrected, my method will deliver potable water without adding lead oriron for a very long time. My methods rejuvenate existing systems andprotect new and future systems from decay due to corrosion.

Although the invention has been described in terms of particularembodiments, one of ordinary skill in the art, in light of the teachingsherein, will be able to generate additional embodiments andmodifications without departing from the spirit of, or exceeding thescope of, the claimed invention. This invention is not limited to usingthe particular elements, materials, or components described herein, andother elements, materials, or components will be equivalent for thepurposes of this invention. Accordingly, it is understood that thedrawings and the descriptions herein are proffered only to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

What is claimed is:
 1. A corrosion prevention system for a potable waterpiping system, wherein the potable water piping system comprises atleast one iron main, possibly one section of non-conductive pipe, and atleast one section of lead pipe, the corrosion prevention systemcomprising: a. iron mains and at least one sacrificial/potential anodeelectrically connected to at least one section of lead pipe, b. wherebyan interior surface of the section of lead pipe is maintained at avoltage above the reduction potential of the redox reaction between ironand the protective concentration of disinfection chemicals, wherein thelead pipe is electrically connected to the iron main.
 2. The corrosionprevention system of claim 1, wherein the sacrificial/potential anode iscomprised of a metal less noble than iron.
 3. The corrosion preventionsystem of claim 2, wherein the sacrificial/potential anode is comprisedof zinc, an alloy thereof, or a metal or metal alloy less noble thanzinc.
 4. The corrosion prevention system of claim 1, further comprisinga DC power source electrically connected to at least one section of ironmain connected to a lead pipe.
 5. A corrosion prevention system for apotable water piping system, wherein the potable water piping systemcomprises at least one iron main, possibly one section of non-conductivepipe, and at least one section of lead pipe, the corrosion preventionsystem comprising: a. at least one insoluble anode, and/or asacrificial/potential anode b. a power source electrically connected tothe insoluble anode, and/or sacrificial/potential anode c. a voltagecontroller electrically connected to the insoluble anode, the powersource, and the lead pipe, d. whereby an interior surface of the leadpipe is maintained at a voltage above the reduction potential of iron,wherein the lead pipe and the iron main are electrically connected 6.The corrosion prevention system of claim 5, wherein the insoluble anodeis comprised of graphite.
 7. The corrosion prevention system of claim 5,wherein the power source comprises a battery or a solar cell and avoltage controller.
 8. The corrosion prevention system of claim 5,wherein the power source comprises an AC/DC rectifier-converter.
 9. Amethod for preventing corrosion of a lead pipe in a potable water pipingsystem, wherein the potable water piping system comprises at least oneiron main and possibly a section of non-conductive pipe, electricallybypassed by an electrical jumper, comprising: a. electrically connectingmeans for corrosion protection to the lead pipe; b. whereby the interiorsurface of the lead pipe is maintained at a voltage above the reductionpotential of iron.
 10. The method of claim 9, wherein the means forcorrosion protection comprises at least one sacrificial/potential anode.11. The method of claim 10, wherein the sacrificial/potential anode iscomprised of a metal less noble than iron.
 12. The method of claim 11,wherein the sacrificial/potential anode is comprised of iron, zinc, oran alloy thereof.
 13. The method of claim 9, wherein the means forcorrosion protection comprises a voltage controller, a DC power source,wherein the voltage controller is electrically connected to the powersource and the iron and lead distribution system. x
 14. The method ofclaim 13, wherein the power source comprises an AC/DC rectifierconverter